Science -- Your Future, Scotland's Future
SCI-FUN Roadshow Exhibits -- Life Through Time
SCI-FUN Roadshow Exhibits -- Life Through Time
SCI-FUN Roadshow Exhibits -- Life Through Time : timescale
SCI-FUN Roadshow Exhibits -- Life Through Time : Palaeozoic era
SCI-FUN Roadshow Exhibits -- Life Through Time : Mesozoic era
SCI-FUN Roadshow Exhibits -- Life Through Time : Cenozoic era
In this exhibit you learn about how we can use fossils to learn about prehistoric life.

Fossils are the preserved remains of once living things. Fossils of long-extinct species can tell us a lot about how life on Earth used to be.

Normally, when living things die, they are quickly decomposed by bacteria and fungi. On rare occasions, they can be preserved as a fossil. For this to happen, the dead organism must be quickly covered by sediment (small particles of rock) to prevent the decomposers from getting to it. The reason so many fossils are only bone is that the rest of the body is eaten or decomposed much more quickly than bone, so often only bone is left by the time the body is covered.

Fossilisation occurs when groundwater, which has minerals dissolved in it, fills in the gaps in and around the organism. The minerals sediment in the gaps, and eventually rock is formed in the shape of the organism. Sometimes fossils form around the outside of the organism, giving an impression, and sometimes they fill the spaces within the organism, giving the shape of the organism.

Fossils are rare because they rely on organisms being covered by sediment. This means that we do not have fossil samples of all the organisms that have ever existed. It is particularly difficult to find fossils of organisms that lived in areas or times where being buried in sediment was unlikely. This is why we do not have a complete fossil record.

The fossil record allows us to compare the species that existed at any given time, and see how evolution has progressed. Fossils allow us to see how our ancestors were and how we came to be. By studying fossils we can see how all life on earth descended from a single common ancestor, and how different species diverged from each other over time.

Some of the most interesting fossils we find come from dinosaurs (they’re giant reptiles: of course they’re interesting) and the early humans, like Neanderthal man. The early human fossils help us to learn where we came from.

The three levels on the exhibit cover three different periods in the Earth's history. From looking at the layer files opposite, you can see the way in which the surface features of the planet have changed over time. The PDF file below shows you a series of images, covering a time-span from over 600 million years ago, to approximately 250 million years in the future.

Maps of the Earth: 650Ma to +250Ma
1 Fossils are the preserved ________ of once living things.
2 What must an organism be covered in, on order to fossilise?
3 What fills the gaps in the organism in fossilisation?
4 Fossils of what organisms are particularly difficult to find?
5 How do we use the fossil record to learn about evolution?
6 What kinds of rocks do you think fossils would most likely form in?

1 Go fossil hunting. Check out to find a good fossil hunting spot near you, normally beaches are the best. Take with you tissue to wrap the fossils in and a bag to carry them home. Turn over rocks to see if there’s a fossil on them. When you get home, use the Internet to find out what they are. When going on a fossil hunt make sure you know the area you’ll be walking or take a map, make sure an adult knows where you are, never go by yourself and always take a mobile phone with you.
2 Fossilise a dead pet. If a pet dies (from natural causes, not you killing it for the sake of an experiment), instead of flushing it down the toilet or burying it in the garden, bury it somewhere it will fossilise. You need an oxygen-free enviroment, such as under a glacier, under the deep sea bed, under larval flow or (slightly easier) a peat bog. After a few hundred thousand years, there’ll be a fossil.